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Old 10-19-2007, 04:37 PM   #1
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Pipe insulation: Foam, Rubber, Other?


I'm planning on insulating some of my pipes and am wondering what the best kind of insulation is. I was checking it out at the hardware store, and there were a couple different kinds; a lightweight foam, similar to a funoodle pool toy, a heavier and more expensive foam rubber, similar to what I've seen used on heat pump lines, as well as some foil backed fiberglass wrap. I'm thinking of using the foam rubber, but only because it's a) more expensive and b) it's what they use on heat pump lines. I'm assuming they would use the most efficient stuff for something like that, and that the cheaper stuff is cheaper for a reason.

Basically, which has the better R-value?

Or is there something else I should consider?

Thanks in advance!

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Old 10-15-2008, 01:28 PM   #2
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Pipe insulation: Foam, Rubber, Other?


The R-Value is basically the same for all the insulation types you mentioned. The foam insulation is extremely flamable , so its not recommended to put foam insulation near your hot water heater (just to be safe). Foam insulation also shrinks when it is put on a hot pipe, which could leave spaces in between pieces. Rubber is good for cold pipes, but is a more expensive insulation. Fiberglass is not flamable and is usually the cheapest. Check out for pricing on foam, rubber, and fiberglass insualtion.


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Old 11-01-2008, 01:57 AM   #3
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Pipe insulation: Foam, Rubber, Other?


PE Foams are fire retardant, but rubber creates a very toxic black smoke which contains halogen.

PE is suitable for temperatures up to 250 F (120C).

Rubber shrinks by more than 25% at the boiling point of water; PE only 3%.

Rubber for cold pipes is not a good idea either as the inevitable condensation reacts with the chloride to create hydro-chloric acid and that corrodes the pipes.

Fiberglass? You mean "the other asbestos"? You can't use that for cold applications as the condensation will be absorbed by the material.

Use PE Foam. Lasts forever. Safe and clean and non-toxic.

Good luck,

Harry
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Old 11-01-2008, 10:43 AM   #4
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Pipe insulation: Foam, Rubber, Other?


Polyurethane is the best for pipes. It should be closed cell to keep from absorbing moisture. Most of the time you only need to insulate the warm pipe unless you have freezing issues.

I have used the gray formed pipe (polyurethane) at the local hardware store for decades and it has worked fine for temperatures ranging from -30 to 160.

My solar hot water system is frying my insulation but it is at 212 on really sunny days and even though it is rated to 230 it is melting.

As for worrying how the stuff will do in a fire that is not really an issue. I mean, what are you doing in a house that is on fire anyhow????
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Old 11-01-2008, 04:18 PM   #5
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Pipe insulation: Foam, Rubber, Other?


PE for cold pipes. Will last about 6 years in UV.

Synthetic rubber(armaflex, armacell) for really hot pipes. It will get brittle and looses R-value with time. Will last about 10 years in UV.

Great stuff foam for either if you don't mind working on it for days. It does have the best R-value though and it heat and flame resistant. Very messy and doesn't look good at all.

Fiber glass is time consuming. has the poorest R-value, and it gets worse if pipes form condensation or are exposed to the elements. It is by far the most heat, flame and U.V. resistant. It needs to be coated with aluminum tape and then duct mastic to make it weather proof. If you don't mind raping every thing 3-4 inches thick then taping and coating, it will handle the most extremes and last the longest.

Their is also cork tape and foamed glass. I wouldn't recommend either.
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Old 11-04-2008, 09:09 PM   #6
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Pipe insulation: Foam, Rubber, Other?


Holy thread necromancy, Batman! I forgot all about the thread until I got an e-mail that someone responded!

And thanks for the responses! For posterity, I did use some PE foam to insulate some of the piping right after the heater. I still haven't finished since the pipe size shrinks once it starts branching out through the house, and I didn't get any of that size yet.

Since a few people mentioned freezing and fire issues, I'll just throw out there that it's an electric heater in the unfinished (but insulated) part of the basement. My main reason for wanting to insulate it is because out hot water heater is set at a pretty low temp, and I want to make sure as much of the heat makes it to where it's being used.

Thanks again!
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Old 11-08-2008, 02:03 PM   #7
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Pipe insulation: Foam, Rubber, Other?


Quote:
Originally Posted by Marvin Gardens View Post
Polyurethane is the best for pipes. It should be closed cell to keep from absorbing moisture. As for worrying how the stuff will do in a fire that is not really an issue. I mean, what are you doing in a house that is on fire anyhow????
With all due respect, Marvin, but I think you may be confused about the PU foam. PU is not completely closed cell (at the most 95%). Put some water on it and see what happens.

One more thing, bacteria are a problem with PU foams, hence there are PU slabs covered with AgION treated aluminum foil. Rubber comes now also in an anti-microbial rubber. But PE is completely mold, mildew, and bacteria resistant.

As for fire, unfortunately, most if not all people who die in a fire have been overcome by the (toxic) smoke. Smoke kills: You can't find the exits, and you can't breathe if it is a rubber fire (rubber insulation contains chloride). PE has an F2 fire rating, and the toxicity and opacity of the fumes are so low that the PE foam can safely be used (and is used) in for instance Airbus aircraft.

As for the temperature range, try using chemical cross-linked PE foam, resistant to 240 degrees F / 120 degrees C.

And regarding UV, no plastic (and also not rubber) likes UV. Cover it with a flexible paint or a UV resistant PE film (some PE foams come with such films).

Greetings,

hmcl
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Old 11-08-2008, 05:53 PM   #8
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I really don't understand what is pe, will be running water to a work shop. `
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Old 11-09-2008, 03:09 AM   #9
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Pipe insulation: Foam, Rubber, Other?


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Originally Posted by raskgle View Post
I really don't understand what is pe, will be running water to a work shop. `
Raskgle
PE stands for poly-ethylene. The insulation made of low density expanded PE (poly-ethylene) is 100% closed cell, and has a constant lambda value, meaning that the insulation applied today, has the exact same performance 25 or 50 years from now.
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Old 01-04-2009, 06:34 PM   #10
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Pipe insulation: Foam, Rubber, Other?


Is PE Foam good for steam pipes from a furnace or are the pipes too hot?

Thanks

Dennis
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Old 01-06-2009, 10:58 AM   #11
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Pipe insulation: Foam, Rubber, Other?


[QUOTE=Densec;206984]Is PE Foam good for steam pipes from a furnace or are the pipes too hot?

Depends.... There is cross-linked PE foam (yes, would be OK), and there is non cross-linked PE foam (nah, not really possible).

With cross-linked foam, the PE molecules are bonded to one another. That results in a higher resistance against chemicals, as well as a higher temperature resistance: Good for up to 110 centigrade / 230 Fahrenheit and a peak of some 10 C / 20 F higher.

With non cross-linked foam, the temp resistance is 95 C / 203 F.

So yes, if you use cross-linked PE. You can recognize cross-linked PE as it has a finer cell structure, and it comes in flat shapes (which, of course, can be made into a tube or a sleeve). If you see a tube or a sleeve made out of one piece of poly-ethylene foam (without it being glued together) it is most likely non cross-linked.
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Old 08-25-2009, 05:13 AM   #12
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Pipe insulation: Foam, Rubber, Other?


Hi,

You all seem knowledgable on insulation materials so I have a few questions that have been batted around on another forum if you dont mind:

1) Does PU sheet insulation lose its lambda (k) value when it gets wet?

2) Does PU sheet insulation break down and disintegrate when it gets wet?

3) Is pentane the blowing agent for PU sheet insulation and if so, does the lambda value depend on the pentane being in the sheet - ie does it lose a significant amount of insulation value over time?

Thanks!

Steve
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Old 10-07-2009, 01:28 PM   #13
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Pipe insulation: Foam, Rubber, Other?


Greetings all,
I am basically in the exact same situation as the OP....found this thread...and want to confirm I got the right conclusion here as there is some highly conflicting information.

My situation is that my hot water heater is in a utility room off a finished basement. But also hot water system has a hot water recirculator in it...so my hot water feed pipes and the return pipes that are in the utility area are throwing off (and therefore wasting) heat in the utility area to the point that the utility area is warmer than the finished basement any time of year... quite warm. So I want to insulate all the hot water feed and return pipes I have access to starting right at the hot water output from the water heater. Been to Lowes/Home Depot and seem to find the three stated options in preformed pipe insulation: 1) PE foam, 2) rubber, and 3) fiberglass with tape covering around it...and I'm trying to figure out what is the "best" way to go. "Best" in my case means getting the highest R value I can in something that will not be or become problematic for any reason...ie. condensation/mold, melting at the hot water output area from the tank, etc.

My conclusions and questions from this thread are:
1) that PE Foam is the way to go. How does it's R value stack against rubber or the fiberglass options? Will I be ok from a melting perspective putting it right at the hot water tank hot output?http://www.homedepot.com/Building-Ma...atalogId=10053
2) Rubber could melt and/or throw off toxic stuff so best used only on cold water pipes? http://www.armacell.com/www/armacell...e?OpenDocument
3) Fiberglass...not sure what to conclude on this other than avoid for cold water which is not something I'm considering. http://www.homedepot.com/Building-Ma...atalogId=10053
.
Economics....
PE Foam is cheapest...~$2 bucks for 6 feet
rubber a bit more money....~$5 bucks for 6 feet
fiberglass sections pre-wrapped with tape ...~$5 bucks for 3 feet

HELP!!!.......
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Old 11-12-2009, 02:33 PM   #14
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Pipe insulation: Foam, Rubber, Other?


Definitely use the self-sealing foam pipe insulation. That's the kind with adhesive pre-applied and covered with plastic strips, so after you install it you pull off the strips and stick it together, to eliminate the gap where the pipe is slit. It costs a little more but will be much more effective. If you want to be really thorough, tape all the connections between pieces of pipe insulation. Don' forget to insulate at least the first 6 feet(from your water heater) of your cold water pipes as well, along with anything else connected to the water heater that feels warm(i.e. electrical conduit, TPR valve)

Foam always has a higher R-value than fiberglass, and since fiberglass is not an air barrier, it would need a completely air-tight covering to achieve it's stated R-value.

As far as which type of foam has a higher R-value, I have spent many hours in vain trying to figure this out and can't get accurate information about R-values for pipe insulation anywhere. Perhaps that's because the R-value standard cannot be applied to pipe insulation due to the testing methods. The closest I've come to this information is here, but the information is inconsistent and doesn't make sense.
In any case I would go with the cheaper polyethylene foam, since I doubt there is much difference R-value and it makes intuitive sense that it would be more durable- rubber hardens over time, but plastic in most forms is extremely stable.

Neither type is going to melt at any temperature your water heater is going to reach. Other posters were referring to smoke hazards in the event of a house fire.

Quote:
Originally Posted by piste View Post
Greetings all,
I am basically in the exact same situation as the OP....found this thread...and want to confirm I got the right conclusion here as there is some highly conflicting information.

My situation is that my hot water heater is in a utility room off a finished basement. But also hot water system has a hot water recirculator in it...so my hot water feed pipes and the return pipes that are in the utility area are throwing off (and therefore wasting) heat in the utility area to the point that the utility area is warmer than the finished basement any time of year... quite warm. So I want to insulate all the hot water feed and return pipes I have access to starting right at the hot water output from the water heater. Been to Lowes/Home Depot and seem to find the three stated options in preformed pipe insulation: 1) PE foam, 2) rubber, and 3) fiberglass with tape covering around it...and I'm trying to figure out what is the "best" way to go. "Best" in my case means getting the highest R value I can in something that will not be or become problematic for any reason...ie. condensation/mold, melting at the hot water output area from the tank, etc.

My conclusions and questions from this thread are:
1) that PE Foam is the way to go. How does it's R value stack against rubber or the fiberglass options? Will I be ok from a melting perspective putting it right at the hot water tank hot output?http://www.homedepot.com/Building-Ma...atalogId=10053
2) Rubber could melt and/or throw off toxic stuff so best used only on cold water pipes? http://www.armacell.com/www/armacell...e?OpenDocument
3) Fiberglass...not sure what to conclude on this other than avoid for cold water which is not something I'm considering. http://www.homedepot.com/Building-Ma...atalogId=10053
.
Economics....
PE Foam is cheapest...~$2 bucks for 6 feet
rubber a bit more money....~$5 bucks for 6 feet
fiberglass sections pre-wrapped with tape ...~$5 bucks for 3 feet

HELP!!!.......
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Old 11-12-2009, 02:55 PM   #15
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Originally Posted by danstheman View Post
Definitely use the self-sealing foam pipe insulation. That's the kind with adhesive pre-applied and covered with plastic strips, so after you install it you pull off the strips and stick it together, to eliminate the gap where the pipe is slit. It costs a little more but will be much more effective. If you want to be really thorough, tape all the connections between pieces of pipe insulation. Don' forget to insulate at least the first 6 feet(from your water heater) of your cold water pipes as well, along with anything else connected to the water heater that feels warm(i.e. electrical conduit, TPR valve)

Foam always has a higher R-value than fiberglass, and since fiberglass is not an air barrier, it would need a completely air-tight covering to achieve it's stated R-value.

As far as which type of foam has a higher R-value, I have spent many hours in vain trying to figure this out and can't get accurate information about R-values for pipe insulation anywhere. Perhaps that's because the R-value standard cannot be applied to pipe insulation due to the testing methods. The closest I've come to this information is here, but the information is inconsistent and doesn't make sense.
In any case I would go with the cheaper polyethylene foam, since I doubt there is much difference R-value and it makes intuitive sense that it would be more durable- rubber hardens over time, but plastic in most forms is extremely stable.

Neither type is going to melt at any temperature your water heater is going to reach. Other posters were referring to smoke hazards in the event of a house fire.
Thanks!! Your screen name is appropriate...you ARE the man!! I still haven't finished sealing all my pipes but did end going with the one you recommend. Was told by one guy at Loew's that 1/2" is standard pipe size but those were WAY too tight on my pipes and would not stay stuck. So ended up with 3/4" which have a "slight" bit of extra room..maybe 1/8" or so between but I figure that's fine.

I actually was planning to do some taping as well like you said. Was thinking duct tape would be fine?...or should I get some "special" tape like shown on the site you sent? Alternatively I was thinking of wrapping some foil backed fiberglass around the PE pipe for added measure with ends secured by duct tape. Reason for foil backed fiberglass is...with the hot water recirculator that I have...my pipes stay hot enough such that when I put my hands on the PE that I've put on the pipes near the water heater they still feel slightly warm.
Thanks again!!

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